Gun charger



Sept. 11,1945. 1 CHAPMAQ 2,384,724

7 GUN CHARGER Filed Nov. 29, 1941 IA 1 1171i"? 1 193 2 i 1 L -1 1- I2 7 ATTORNEY Patented Sept. 11, 1945 TENT OFFICE. r

' GUN CHARGER James E. Chapman, Los Angeles, G'alili, assignor to North American Aviation, Inc., Inglewood, Calif, a corporation of Delaware Application November 29, 1941, Serial No. 420,957

1 Claim.

.The present invention relates generally to machine guns, wherein the feed of shells to the guns is dependent in operation upon recoil operated feed means. In the event of failure of a shell to fire, there is no recoil to continue feed and this must be accomplished by manual withdrawal of the gun bolt to eject the unfired shell and manual feed of another shell, or some means automatically accomplishing the same.

It is the primary object of the present invention to provide for the automatic chargin of a machine gun by electrically actuated means at any point in the operation of the gun when a normalcharging .recoil is delayed for a certain period.

. It is a further object, in thus providing for electrical charging, under the above circumstances, to provide a charging mechanism which will be placed in potentially operative condition upon the closure of the switch energizing the usual gun firing solenoid, the charging mechanism thereafter continuing in a condition ready for effective operation should recoil be delayed over a predetermined period at any timeduring gun operation.

A further object in providing for electrical charging is to minimize the necessary mechanical connections involved in withdrawal of the gun bolt, so as to conserve space and thus readily adapt the invention to use where, as in airplanes, the gun must be used in. a small space.

With the foregoing and other objects and advantages in mind, the best mode thus far devised for carrying the invention into practical effect will be described in suflicient detail fora thorough understanding and appreciation of the invention by any one skilled in this art, with reference to the accompanying drawing, which forms a part of this specification, and in which,

Fig. 1 is a top plan view illustrating the practical application of the mechanical portions of the present invention to a gun shown more or less in diagram.

. Fig. 2 is a side view of the parts appearing in Fig. 1.

Fig. 3 is a detail vertical, transverse sectional view through certain of the parts, taken. substantially on line 33 of Fig. 2.

Fig. 4 is a diagram of a suggested electrical control for the device.

Referring now to the above mentioned figures and particularly to the mechanical aspects of the invention, as illustrated in Figs. 1, 2 and. 3, it is proposed to mount a frame at one side of the gun, indicated at A, of a character adapted to form a support for a motor and reduction gear housing II, situated so that its driven or low speed shaft l2 projectslaterally into the limits of frame ID at a point approximately centrally between the frame ends.

The frame It is. securely positioned so that its forward end is forwardly beyond the laterally projecting gun bolt A which in normal operation travels rearwardly, compressing the bolt spring A and permitting discharge of a spent shell, and then forwardly under the impetus of spring A for charging the gun with a new shell. It is understood, of course, that in normal operation the movements just mentioned result from the recoil of each firing operation and that, in the event of failure of a shell to fire, there is no recoil and no automatic rearward movement of the gun bolt A.

The frame Ill also forms a guiding support for a lengthwise slidable rack bar l3 which in its forward position extends forwardly of the frame, and in its rearmost position, extends rearwardly thereof, as respectively shown in full and dotted lines in Fig. 2. The lower toothed surface of the rack bar 13 is operatively engaged by a pinion M on the driven shaft 12 sothat upon motor actuated rotation of pinion M in a clockwisedirection, as in Fig. 2, the rack will be shifted lengthwise and rearwardly in a plane parallelv to the gun A and corresponding to the normal rearward movement of the gun bolt A, from the position shown in full lines in Fig. 2 to the position shown in dotted lines. When. the pinion is rotated in the opposite direction the rack is moved forwardly to the full line position.

At one side of the rack l3 intermediateits ends, a bolt engaging dog I5 is pivoted at I6 to rise and fall. This dog has upper and lower side recesses 50 to receive a spring pressed latch ball i! carried by the rack bar i3, as in Fig. 3, and the dog is also provided with an upper, rearwardly facing, angular, bolt engaging nose '48 and a .rearwardly and downwardly inclined tail 49. At the forward lower portion of frame in, a cam block [8 is stationarily supported so that when the rack bar I3 is shifted forwardly to the normal full line position of Fig. 2, the tail 49 of the dog rides on cam block I8 and shifts the dog to its upper spring-latched position with its upper nose 48 forwardly of, and in line with, the gun bolt A. Thus upon rearward movement of the rack bar, under motor actuation, dog IS in its upper effective position engages the gun bolt A and forces the latter rearwardly for its full stroke during which, as above stated, the bolt spring A isplaced under compression.

As the bolt A reaches the end of its rearward stroke, the tail 49 of the dog l5 encounters a pin is which causes downward shifting of the dog l5 from its upper latched position to its lower latched position and withdraws its nose from engagement with the bolt A so asto free the latter. As soon as it. is thus freed, the bolt A moves forthe gun with a newly fed shell. Thereupon, a re- I3 is provided at its opposite ends with depending fingers 25 and 2| for shifting at the ends ofits movements, the grounded single pole, double throw reversing switch 22 of the circuit of a split-field, reversible motor 23, as indicated in the diagram of Fig. 4.

Within the motor circuit of Fig. 4, to which current is aVailable whenever'the main switch 24, or firing key, is closed for supplying current from feed line 25 to the gun firing solenoid line 26, is a time-delay switch 21 that remains inactive as current is normally utilized in the regular firing of the gun. It will be noticed that the contacts (indicated by arrows) in the time-delay switch 21 are normally spaced apart. When they become heated, the metal of which they are formed expands sufiiciently for the contacts to engage each other. In the, normally brief intervals between firing of the gun, the gun bolt A momentarily closes a switch 33 (which is nor-.

mally open). This momentary closing of the switch 33 closes the following circuit: feed line 25, switch 24, resistance 5|, wire 29, switch 33, wires 52 and 53, switch 22, and its ground.

During this momentary closing of the switch 33, which is at the time the gun bolt is in its forward or charging position, the resistance 5| does not heat up sufficiently to close the contacts 21. (What is herein termed the charging position is to be taken to mean the forward, full line position in Fig. 2.) However, when the gun fails to fire, the gun bolt A continues to maintain the switch 33 closed, thus permitting the resistance 5| to heat up. The resistance 5| is arranged sufficiently close to the spaced.- contacts 21, to heat such contacts to the point where they engage each other, when the circuit of the resistance 5| is maintained closed longer than the momentary closing of normal firing of the gun.

Engagement of the contacts 21 with each other completes the following circuit: feed line 25,

switches 24 and 21, wire 3|, electro-magnet 32, wires 3|] and 53, switch 22 and its ground.

When electromagnet 32 is thus energized it draws armatures 34 and 35, respectively, against contacts 35 and 31, the former of which is connected to feed line 25 and the latter grounded. With reversing switch 22 in the position shown in Fig. 4, a holding circuit is thus formed through contact 35, armature 34, wire 38, wire 3|, electromagnet 32, from the feed line 25 to the grounded reversing switch 22. At the same time current flows from feed line 25 through the motor 23 and its field 39 in the direction of arrow ll through armature 35, and contact 31 to ground, so that the motor operates in a direction to shift the rack bar 3| to the right for retracting the gun bolt A from charged position. This permits switch 33 to open, thus breaking the time relay circuit, and the rack bar 3| continues to move rearwardly through its bolt retracting stroke until its projection 25 engages reversing switch 22 and shifts the same from contact with line 35 to contact with line 4|, during which reverse of switch 22 the holding circuit is broken, armatures 34 and 35 return to their normal positions as shown, and the motor circuit through field 39 is broken. Upon reverse of switch 22, however, current flows from the feed line through motor 23 and its field 42 in the direction of arrow 43, thus reversing the motor and causing movement of the rack bar to return to its forward position at which its projection or finger 2| again shifts the reversing switch 22 to the position shown in Fig. 4. In the meantime the return of the gun bolt A to charging position, closes the switch 33 and the various parts are thus restored to a position ready for the next similar operation required of them in the case of failure of the gun to fire.

The mechanism thus provides, within a relatively short period after failure of the gun to fire, for retraction'of the gun bolt and the recharging of a new shell, without requiring any at tention on the part of the operator or any of the diificulties existing at present in a recharging operation after firing failure due to a defective shell.

While I have illustrated and described what I now regard as the preferred embodiment of my invention, the construction is, of course, subject to modifications without departing from the spirit and scope of my invention. I, therefore, do not wish to restrict myself to the particular form of construction illustrated and described, but desire to avail myself of all modifications that may fall within the scope of the app nded claim.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

For an automatic gun having a charging mechanism and a bolt adapted to reciprocate continuously, longitudinally of the gun during gun firing to operate said mechanism, said bolt remaining in a forward position for a normal period of time during each reciprocation; an auxiliary charger comprising areciprocable rack, means on said rack adapted to engage and retract the bolt from its forward position when said rack is moved'in one direction from a normal position and said means constructed and arranged to release said bolt at the end of the bolt retracting movement, electrically operated motor means connected to said rack for reciprocating the same, said motor means comprising a circuit, a motor switch in said circuit to control the operation of said motor means for moving said rack in bolt retracting movement and a reversing circuit to reverse the operation of the motor means for returning said rack to said normal position, a motor switch control means comprising a relay circuit including a relay constructed and arranged to close said motor switch, a time delay device in said relay circuit for controlling the energization of said relay comprising an actuating means constructed and ar:-. ranged to be operated by the bolt only when the bolt is in its forward position for a period of time longer than said normal period of time, a double throw switch constructed and arranged to be included in said relay circuit in a first position and in said reversing circuit in a second position, means on said rack for moving said double throw switch from said first position to said second position at the end of the bolt retracting movement to open said relay circuit and to close the reversing circuit to return said rack to said normal position.

' JAMES E. CHAPMAN. 

